AutoCodes – Generic – P2179

P2179 Code - System Too Lean Off Idle Bank 2

Quick Answer

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. Common causes include Intake air leaks, Faulty front heated oxygen sensor, Ignition misfiring. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P2179 indicates System Too Lean Off Idle Bank 2.
Common causes: Common causes include Intake air leaks, Faulty front heated oxygen sensor, Ignition misfiring.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 36,822

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P2179 Description

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.

In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).

OBDII Code P2179 - System Too Lean Off Idle Bank 2 - AutoCodes.com — P2179 Code - System Too Lean Off Idle Bank 2

What does this mean?

What are the Possible Causes of the DTC P2179?

Intake air leaks
Faulty front heated oxygen sensor
Ignition misfiring
Faulty fuel injectors
Incorrect fuel pressure
Lack of fuel
Faulty Mass Air Flow (MAF) sensor
Incorrect Positive Crankcase Ventilation (PCV) hose connection

How to Fix the DTC P2179?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Then engine is "too Lean" when the O2 sensors detect more air than fuel during combustion. There are two likely issues for a lean system problems. One of the problems could be unmetered air is entering the engine, in other words there is an air intake leak after the Mass Air Flow (MAF) sensor. The other problem could be clogged fuel injectors. Fuel additives sometimes will fix clogged fuel injectors.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2179 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Information for Specific Makes

P2179 Dodge — System Too Lean Off Idle Bank 2
P2179 Mazda — System Too Lean At Off Idle Left Bank

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.